Question regarding the overdrive feature on my car?

Good morning.

Yesterday as I was driving home in my Nissan Versa sedan, I noticed an indicator light reading "OD OFF" on my dashboard. I had no idea what that refers to, and therefore opted to keep driving. When I got onto the highway, I noticed that the engine was revving and making significantly more noise than usual - at approximately 65 - 70 mph, it sounded as if I were going at least 20 miles above that. At this point I became worried, but being clueless about mechanics and not wanting to give in to panic by pulling over and having the car towed, I once again elected to proceed. Finally, I pulled into a supermarket parking lot and consulted the owner's manual (which, granted, I probably should have done right away). In any event, I discovered that "OD" stands for "Overdrive", and that it had evidently been turned off. I couldn't tell where the on/off button for that was based on anything I found in the owner's manual, but eventually located it, roughly three inches down the gear shift lever. Everything went back to normal after that. When I got home, I checked the "Overdrive (mechanics)" article on Wikipedia, and discovered the following: "Overdrive (OD) is a term used to describe a mechanism that allows an automobile to cruise at sustained speed with reduced engine RPM, leading to better fuel economy, lower noise and lower wear." I therefore have three questions:

-Why is there even the option to turn the overdrive feature off? Are there ever any circumstances wherein it's advantageous to do this?

-I trust having driven roughly 30 miles with OD turned off (I still can't for the life of me figure out how I accidentally did this, by the way) isn't likely to have any long-term effects on my car?

-Should this ever happen again, is it safe to turn OD back on while driving, or is it necessary to pull over first?

Thank you in advance, car people, for indulging my cluelessness.

2012-08-02T07:15:04Z

Adam, if you'd read my question in its entirety (particularly towards the end), you'd have seen that I wasn't asking for a definition of "overdrive". Thank you anyway. ;-)

?2012-08-02T07:15:46Z

Favorite Answer

you can switch it ON / OFF while driving

the only time I can think of that it would be good to switch it OFF would be in extreme hilly / mountainous driving

its "automatic overdrive "...so unles you switch it off, it takes care of itself,

Anonymous2012-08-02T07:11:45Z

Overdrive is a gear in your transmission which allows the vehicle to operate at high speeds while keeping your engine RPMs down. This gives you better gas mileage and reduces the strain on your engine. Your engine was making noise because with the OD off you were most likely operating the engine at high RPM's at those speeds. The OD button should be on the side of the gear selector. You can turn on the OD button while driving.

?2016-12-14T17:44:23Z

Nissan Versa Overdrive

Uncle Regino2012-08-02T07:14:14Z

OD should be On all the time. the car will use it only if it need it. The only time when you don't use OD is when you are towing something or driving on a road full of hills , up and down. Your car has a CCVT ( continous variable transmission) so it will do everything by itself, Just leave the OD on, unless you are following a bunch of trucks , vans on a hilly landscape where you will need more power to pass them.

Anonymous2016-04-11T03:44:28Z

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it puts the transmission into a slightly bigger gear to improve fuel economy. main use is on the highway.